I'm working on a basic physics lab report (not homework) and I'm trying to understand something better. We're establishing a relation between voltage and current using Ohms law. It goes as follows:(adsbygoogle = window.adsbygoogle || []).push({});

We apply different voltages to two materials and record the current in order to determine the resistance. The two materials are a resistor and a light bulb. My problem has occured when graphing though.

I know that the relationship for an ohmic material is linear, therefore it's simply (1/R). This would be true for the resistor. The lightbulb however is a nonohmic material, therefore it's not a linear relationship.

The way my graph looks is not the same as in the book though. The book shows a graph which looks like an exponential function (x^2), approaches a verticle asymptote. My graph for the lightbulb though looks opposite (looks more like a sqrt function) and approaches a horizontal asymptote. When looking online I saw a V versus I graph for a filament and it looked the same as mine.

My question is, why is this? Why do I have a different graph than what the book shows for a nonohmic material, but I see other "filament" graphs look the same as mine.

Thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Voltage and Current lab report help

**Physics Forums | Science Articles, Homework Help, Discussion**